Lymphocytes bearing the gamma delta T-cell receptor in normal human intestine and celiac disease

Monoclonal antibodies to T-cell receptors were used to investigate the prevalence of the two distinct T-cell subpopulations (TCR alpha beta+ and TCR gamma delta+ cells) in the intestinal mucosa of children with celiac disease (gluten-sensitive enteropathy) as compared with normal intestinal mucosa. TCR gamma delta+ cells were rarely identified in the epithelium of human fetal or normal postnatal intestine and few were present in the lamina propria, whereas the number of distribution of TCR alpha beta+ cells closely resembled that of CD3+ cells. Compared with normal intestine, a significant increase in the number of CD3+, CD8+, TCR alpha beta+, and TCR gamma delta+ intraepithelial lymphocytes was present in celiac disease. Although the mucosal TCR gamma delta+ cells were less numerous than TCR alpha beta+ cells in celiac disease, there was a marked increase in the number of TCR gamma delta+ cells as compared with controls. The ligand recognized by the gamma delta T-cell receptor and the function of these cells have not been determined; however, these findings suggest a possible role for TCR gamma delta+ lymphocytes in mucosal immune responses and tissue injury as seen in celiac disease.

Autoimmune enteropathy and nephropathy with circulating anti-epithelial cell antibodies

We describe a child with circulating anti-epithelial cell antibodies, autoimmune enteropathy with intestinal villous atrophy, and membranous glomerulonephritis. The patient had persistent diarrhea at 6 months of age, and a small bowel biopsy showed active enteritis, villous atrophy, and crypt hyperplasia. When the patient was, 10 months of age, nephrotic syndrome developed because of membranous glomerulonephritis. Results of tests for circulating immune complexes were negative. Indirect immunofluorescence studies revealed a circulating antibody directed against renal epithelial cells. Circulating antibodies directed against normal small intestine epithelial cells were also detected by the immunoperoxidase technique. Western blot and immunoprecipitation identified a 55-kd antigen, in both small bowel and kidney, that reacted with an antibody in the patient's serum. High-dose prednisone therapy induced a clinical remission, resolution of the small bowel injury, and diminished serum anti-epithelial cell antibodies; after dose reduction, clinical relapse occurred with villous atrophy and reappearance of anti-epithelial cell antibodies. When the patient was 45 months of age, persistent diarrhea recurred despite intravenous administration of corticosteroids, cyclosporine, and total parenteral nutrition. Autoantibodies to a 55-kd epithelial cell protein are temporally related to the development of enteropathy and nephropathy. Study of similar patients is needed to determine the role of such antibodies in this disorder.

Immunology of inflammatory bowel disease: summary of the proceedings of the Subcommittee on Immunosuppressive Use in IBD

As outlined, scanty data exist with regard to immunologic therapy in children with IBD despite the fact that the pediatric population affords a unique opportunity for clinical evaluation. Children are less affected by modifying conditions such as smoking, alcohol ingestion, and the long-term use of medications, and because of their specific needs for ponderal and linear growth, children might benefit most from immunological therapy that has been proven to be steroid sparing. Therefore, clinical trials to evaluate the efficacy of 6-MP and/or azathioprine in growing children with Crohn's disease would appear to provide a fruitful avenue for collaborative research. Efforts to organize a multicenter evaluation of these agents have been initiated. The studies are crucial in evaluating the efficacy and safety of immunosuppressive therapy in the pediatric population with IBD.

Malnutrition and carbohydrate malabsorption in children with vertically transmitted human immunodeficiency virus 1 infection

The nutritional needs of children with human immunodeficiency virus infection are poorly understood. Twenty-eight children with vertically transmitted human immunodeficiency virus infection were evaluated for carbohydrate malabsorption using lactose hydrogen breath tests and d-xylose absorption studies. Lactose malabsorption was a common finding in human immunodeficiency virus-infected children and occurred in 8 of 20 patients who had no identifiable enteric pathogen. Lactose malabsorption occurred at an earlier age in human immunodeficiency virus-infected children than in an age-matched group of 45 symptomatic control children (P = 0.02). However, lactose malabsorption was not associated with higher rates of diarrhea or growth failure. Abnormalities in d-xylose absorption were not significantly associated with either diarrhea or growth failure. However, 39% of d-xylose studies (9 of 23) showed abnormal results and were significantly associated with enteric infections (P = 0.004). Abnormalities in small-bowel morphology were found in 4 of 9 children with growth failure, 3 of whom had an enteric infection and low d-xylose absorption. Lactose hydrogen breath testing and d-xylose testing showed carbohydrate malabsorption in 61% of children (17 of 28). This study demonstrates that human immunodeficiency virus-infected children are at risk for malabsorptive disorders, which are not always related to clinical symptoms. We speculate that human immunodeficiency virus may be directly involved in the development of lactose malabsorption. Carbohydrate malabsorption in human immunodeficiency virus-infected children may not be the only factor responsible for growth failure.

Cloning of a human homeobox gene that resembles a diverged Drosophila homeobox gene and is expressed in activated lymphocytes

A new homeobox gene, HB24, has been isolated from a human B-lymphocyte cDNA library. Northern blot analysis of polyadenylated RNA purified from activated human B cells revealed a single mRNA transcript of approximately 2.3 kb. Two cDNA clones were sequenced and provided 2,250 nucleotides (nt) of DNA sequence information. There is a single methionine codon-initiated open reading frame of 1,458 nt in frame with a homeobox and a CAX repeat, and the open reading frame is predicted to encode a protein of 51,659 daltons. When the homeodomain from HB24 was compared to known mammalian and Drosophila homeodomains it was found to be only moderately conserved, but when it was compared to a highly diverged Drosophila homeodomain, H2.0, it was found to be 80% identical. The HB24 mRNA was absent or present at low levels in normal B and T lymphocytes; however, with the appropriate activation signal HB24 mRNA was induced within several hours even in the presence of cycloheximide. Characterization of HB24 expression in lymphoid and select developing tissues was performed by in situ hybridization. Positive hybridization was found in thymus, tonsil, bone marrow, developing vessels, and in fetal brain. HB24 is likely to have an important role in lymphocytes as well as in certain developing tissues.

Human intestine matures as nude mouse xenograft

This report describes a novel system for the study of the development and function of human intestine. Human fetal bowel transplanted into a subcutaneous tunnel on the back of athymic nude (nu/nu) mice develops a new microcirculation within 4 weeks. Tissues undergo morphological development, become similar to adult human bowel tissue, and may survive for 6 months after transplantation. Monoclonal antibody immunoperoxidase staining shows that the epithelial and some endothelial elements are of human phenotype, but the circulating blood cells and migrating mucosal lymphocytes are of mouse origin.

Azathioprine in the treatment of children with inflammatory bowel disease

During a 6-year period, we treated 21 patients with azathioprine, 2 mg/kg/day, as an adjunct to their customary regimen. Nine patients had ulcerative colitis and 12 patients had Crohn disease; the patients' ages ranged from 3 to 17 years. The median duration of disease before the start of azathioprine therapy was 2 years, and median follow-up was 2 years. Sixteen patients seemed to respond to azathioprine therapy: six patients in each disease group had complete responses and four patients (one with ulcerative colitis and three with Crohn disease) had partial responses. Two patients with ulcerative colitis and three patients with Crohn disease did not respond. The median time until patients responded was less than 3 months for patients with ulcerative colitis and 4 months for those with Crohn disease. Reduction of corticosteroid dose was possible for all patients who responded to azathioprine therapy. Only minimal side effects were attributable to the drug. We conclude that azathioprine is an effective adjunctive agent for the treatment of inflammatory bowel disease in childhood, but because questions remain regarding its long-term safety, its use should be reserved for children with refractory disease or severe and unacceptable side effects of corticosteroids.

The distribution of T and B lymphocyte populations and MHC class II expression in human fetal and postnatal intestine

The development of the intestinal mucosal immune barrier is an important protective adaptation for postnatal life. The distribution and phenotype of T and B lymphocytes in human fetal intestine and lymphoid tissues have been characterized and compared to the distribution and phenotype of lymphocytes in postnatal intestine. The characterization of lymphocyte phenotype and MHC class II antigen distribution was done using MAb and an avidin-biotin complex immunohistochemical staining technique. Intraepithelial lymphocytes were occasionally present in fetal intestine and were primarily CD3+, CD8+. T lymphocytes were readily identified in the lamina propria of fetal intestine, but most were clustered in lymphoid aggregates. Cells identified by anti-IgA1 and anti-IgA2 were the most numerous cells of B cell lineage in the lamina propria of postnatal intestine, whereas IgM+ and IgD+ lymphocytes predominated in fetal tissues. However, IgA-bearing cells were identified in lymphoid aggregates of the intestine or spleen of some fetuses. This finding suggests that B lymphocytes can undergo Ig switching in utero. Additionally, fetal intestinal epithelial cells did not express MHC class II antigens, unlike some postnatal intestinal tissues. It is possible that postnatal events such as antigen exposure may be important for the induction of these class II antigens on intestinal epithelial cells.

Allergy-related proctocolitis in infants: diagnostic usefulness of rectal biopsy

To evaluate the diagnostic utility of rectal mucosal biopsies in infants with proctocolitis, we compared the clinical and histologic features of an allergy-related group (N = 36) with those of normal (N = 12) and inflammatory (N = 8) controls. Clinical features were nondiscriminatory among the three groups of patients, except for an increased absolute peripheral eosinophil count in the allergic group. Similarly, morphologic evidence of proctitis (cryptitis and crypt abscesses) and small or moderate numbers of eosinophils (less than or equal to 60 per ten high power fields) in the lamina propria of the biopsies did not discriminate among the three groups. However, large numbers of eosinophils (greater than 60 per ten high power fields) and eosinophils located in the muscularis mucosae or as the predominant cell in crypt abscesses were significantly associated with allergy-related disease. No histologic features of chronic colitis were noted in the allergy-related group. Thus, in tandem with the remainder of the clinical data, rectal mucosal biopsy is a useful adjunct in the diagnosis of allergic proctocolitis.

Expression of immune sensitization to epithelial cell-associated components in the cotton-top tamarin: a model of chronic ulcerative colitis

Chronic colitis is present in up to 50% of adult cotton-top tamarins, but the etiology is unknown. To explore one putative immunopathogenic pathway for the chronic colitis, we determined whether immune sensitization to macromolecules associated with mucosal epithelium of intestine (designated ECAC) had occurred in this primate species. Specifically, we sought to define (a) whether antigenic determinants associated with ECAC are present on tamarin gut epithelium in vivo; (b) if immunoglobulin, capable of binding ECAC, is detectable in tamarin serum; (c) whether the presence of ECAC-specific immunoglobulin is positively correlated with age of the animal or the severity of the colitis, or both; and (d) the number of glycoprotein fractions composing ECAC (denoted as P1 through P4) that are reactive with tamarin immunoglobulin. Expression of ECAC was found by immunofluorescence using characterized oligo-specific or monoclonal antibody: tamarin intestinal epithelium--but not lamina propria, muscularis mucosae, subserosa, or glycocalyx--demonstrated determinants of the ECAC antigen system. Furthermore, coded sera from 10 tamarins with biopsy-proven inflammation involving colonic intestinal mucosa and in which disease activity was moderate to severe showed ECAC-specific cytotoxicity of 3.6% +/- 1.6%. Test values for 9 of 10 of those animals were above the upper limit of normal for the assay (2.1%), and exceeded the level of lysis found with serum from histologically normal tamarins less than 2 yr old (less than 0.3%). When the data were reanalyzed by age of the animal, the incidence of ECAC-specific cytotoxicity correlated with age greater than 2 yr (r = 0.86, p less than 0.001). Epithelial cell-associated component-specific serum binding was confirmed by a second methodology (enzyme-linked immunosorbent assay), where the A405 for tamarins with lesions of moderate-severe grade (0.35 +/- 0.26) clearly exceeded that for young tamarins who were histologically normal (0.02 +/- 0.039) (p less than 0.05). Most of the reactivity was directed toward the P1 fraction of ECAC. Thus, immune sensitization to a fraction of macromolecules associated with colonic epithelium has been found in the cotton-top tamarin, analogous to findings in humans with chronic inflammatory bowel disease.

Esophageal adenocarcinoma 20 years after esophageal atresia repair

We report a case of esophageal adenocarcinoma 20 years after esophageal atresia repair. From one case report it is premature to recommend cancer surveillance for all esophageal atresia patients. However, the first survivors are now reaching an age when esophageal cancer related to chronic esophagitis may become more prevalent.

The alpha 1-antitrypsin gene is expressed in a human intestinal epithelial cell line

alpha 1-Antitrypsin (alpha 1-AT) is considered a typical plasma protein and a prototype of the serine proteinase inhibitor (serpin) family. It is synthesized in hepatocytes and, to a lesser extent, in macrophages. In this study we show that the alpha 1-AT gene is also expressed in human intestine and in a human colonic epithelial tumor cell line, Caco2. A single 1.6-kilobase alpha 1-AT-specific mRNA is present in jejunum and in Caco2 cells. It is identical in apparent size to that present in human hepatoma HepG2 cells but slightly smaller than that present in human macrophages, cells in which an alternative upstream transcriptional start site is used. Synthesis and secretion of alpha 1-AT in Caco2 cells is similar to that in HepG2 cells. It is synthesized as an approximately 52-kDa precursor polypeptide, converted to its mature, fully glycosylated 55-kDa form intracellularly, and the native protein is secreted with a half-time of 37 min. Functionally active alpha 1-AT is secreted into the basolateral and apical (luminal) fluid in pulse-chase labeling experiments of Caco2 cells cultured in polarized orientation on collagen-coated nitrocellulose membranes. Expression of alpha 1-AT in Caco2 enterocytes is not affected by soluble factors that regulate expression of alpha 1-AT in macrophages and hepatocytes. However, expression of alpha 1-AT increases markedly in Caco2 cells as they differentiate into enteric villous-type cells.

Surgical treatment of pancreas divisum causing pancreatitis in children

Although controversial, pancreas divisum has been implicated as a cause of acute pancreatitis when there is stenosis of the accessory papilla that drains the duct of Santorini. Over the past 5 years, four children with pancreas divisum and recurrent pancreatitis were successfully treated surgically. The diagnosis was made by endoscopic retrograde cholangiopancreatography (ERCP) in each case. Surgical treatment included sphincteroplasty to the accessory papilla to improve drainage of the duct of Santorini, opening the ampulla of Vater to expose the ostium of the duct of Wirsung to enlarge it, and cholecystectomy.

Gastrointestinal syndromes associated with food sensitivity

A wide range of clinical syndromes exist that are related to adverse reactions to dietary proteins and that affect predominantly the gastrointestinal tract of infants and children. Experimental data suggest a critical role for developmental alterations affecting intestinal permeability and the mucosal immune response that predispose to these conditions. The diagnostic and therapeutic approach to these disorders varies depending on the nature of the presumed offending antigen, the anatomic site affected, the severity of the inflammatory process, and the implications for future dietary and medical management. Ultimately, the proof that a particular dietary antigen is responsible is dependent on observing the response to oral challenge.

Long-term evaluation of esophageal and pulmonary function in patients with repaired esophageal atresia and tracheoesophageal fistula

Patients who have undergone repair of esophageal atresia and tracehoesophageal fistula as infants have been noted to have residual esophageal dysmotility and pulmonary dysfunction during their childhood years. However, limited information is available about the long-term follow-up of these patients. In this study we performed esophageal and pulmonary function studies on 12 adults who had required surgical repair of these defects in the first week of life. Most patients had symptoms of dysphagia and heartburn at time of evaluation. Pathologic gastroesophageal reflux was documented in 67% of patients and esophagitis was noted in 34%. All patients had esophageal motility abnormalities characterized by low-amplitude nonperistaltic waves throughout most of the esophagus. In addition, although most patients had no respiratory symptoms, mild restrictive lung volumes were noted in many patients. However, airflow obstruction and airway hyperreactivity were not present. These data demonstrate that clinical symptoms and abnormal esophageal manometry and pulmonary function persist well into the third and beginning of the fourth decade after repair of esophageal atresia and tracheoesophageal fistula in infancy.

Pyloric stenosis and eosinophilic gastroenteritis in infants

Eosinophilic gastroenteritis is known to cause gastric outlet obstruction in adults, but has been reported only rarely in infants presenting with pyloric stenosis, a common form of gastric outlet obstruction in children. We describe two infants who presented with classic clinical and radiographic evidence of pyloric stenosis and who were found to have histologic evidence of eosinophilic gastroenteritis on gastric antral biopsies. Their presentation is compared with the clinical and laboratory findings of 47 other infants with pyloric stenosis.

The treatment of post-operative and peptic esophageal strictures after esophageal atresia repair. A program including dilatation with balloon catheters

Nine patients, 6 weeks to 17 years of age with esophageal atresia (EA), developed esophageal strictures and were treated with 26 balloon catheter dilatations over a period of 3 years; 6 are now asymptomatic. Five of the 9 patients had suspected reflux esophagitis, confirmed in 3 by biopsy and treated medically prior to dilatation. Seven of the 9 patients had a primary anastomosis, 1 a gastric tube, and 1 a colonic interposition. Most dilatations in the group of 7 were performed with balloon (B) greater than or equal to the diameter of the distal esophagus (E) (B/E greater than or equal to 1). The 3 residually symptomatic patients include an infant dilated conservatively (B/E less than 1) to facilitate later bouginage, 1 patient with a recurrent stricture after stopping medical therapy and home bouginage, and 1 infant who had a persistent anastomotic stricture, suspected but untreated reflux esophagitis, and a perforation during the second balloon dilatation. Balloon catheter esophageal dilatation, as an alternative to bouginage, is usually a safe and effective procedure when reflux esophagitis is diagnosed and treated prior to dilatation.

The use of nifedipine for the treatment of achalasia in children

Four adolescents with achalasia were treated with nifedipine. All the patients' symptoms improved dramatically. On manometric evaluation, following oral nifedipine, the lower esophageal sphincter pressure decreased approximately 50%. No change in esophageal peristaltic activity was noted. Side effects were minimal; two patients had mild headache initially. Nifedipine, which is commonly used in adult patients with achalasia, may be beneficial for short-term symptomatic relief in children until more definitive therapy can be performed.

Chronic diarrhea associated with hypogammaglobulinemia and enteropathy in infants and children

In order to define the gastrointestinal manifestations and small intestinal structure and function in a group of infants with chronic nonspecific diarrhea and hypogammaglobulinemia, we retrospectively identified 55 such patients from a population of 518 children evaluated for chronic diarrhea over a 6-year span (10.6%). All patients had IgG levels 2.0 SD or more below the mean values for age. Patients with biochemical evidence of protein loss (enteropathy or nephropathy) were excluded. There was a 50% incidence of small intestinal mucosal injury among these patients, with a spectrum of morphological findings ranging from healing enteritis to severe active enteritis. Carbohydrate malasorption, and infection with Giardia lamblia or Clostridium difficile occurred in 34% and 24% of patients tested, respectively. These structural, functional, and infectious complications were all statistically more common in patients than in a control group of children with chronic diarrhea, normal growth, and normal immunoglobulin levels. This study suggests that immunoglobulin determination, in children who would otherwise carry a diagnosis of chronic nonspecific diarrhea, identifies a group with hypogammaglobulinemia, having an increased incidence of treatable intestinal dysfunction or infection, and a spectrum of small intestinal histologic abnormalities.